This invention relates to a robot, a robot system, and a robot control method in which a robot is connected to a network, and the functions of robot input/output, robot control, failure diagnosis, maintenance, etc., are performed via the network.
Conventionally, one or more industrial robots have been installed in a factory or in other similar buildings so as to perform the welding, conveyance, and assembly of components of products. In recent years, with the systematization and efficiency improvements in manufacturing environments such as that of a factory, cases have increased in which a medium-or large-scale production line is formed, and a plurality of industrial robots are installed as equipment for carrying out manufacture and inspection so as to construct a 24-hour operation of a mechanized production line in a manufacturing environment. In that case, as a robot-installing method, a method is employed in which the robot is installed in the vicinity of the production line of a belt conveyer, and is operated synchronously with the belt conveyer and with other equipment or is controlled synchronously with the operation of other robots and in a working condition.
In order to synchronize the robot with other robots or with a production line of a belt conveyer or the like, there has been employed a method of connecting a robot sequencer by which an input/output function of the robot is performed directly to input/output portions of the other robots or the conveyer, or a method of installing one or more controllers, such as programmable logic controllers, in the factory, thereafter connecting the input/output portions of the robots or the belt conveyer to the input/output portions of the controllers by means of lines, and allowing the controller to centrally control the equipment installed in the factory.
In the conventional technique, there is a need to physically connect the robot sequencer to the input/output portion of the equipment in the factory by means of lines, and, in order to connect a plurality of input/output terminals to each other, there is a need to connect the input/output portions by use of, for example, parallel cables that are made up of lines corresponding to the number of terminals. However, disadvantageously, if the number of pieces of equipment to be connected increases, the number of cables increases correspondingly, and, if the distance between pieces of equipment increases, that, of the cables increases correspondingly. Accordingly, a problem resides in that a space is required to dispose the cables in the factory, and the cost of preparation of the cables rises.
Further, in order to perform a logical operation for input/output information from one or more pieces of equipment and determine a command to control the one or more pieces of equipment on the basis of its result, a method is employed in which all the pieces of equipment are connected to a controller such as a programmable logic controller, and a logical operation is performed by the controller, and the result is output to the equipment to be controlled. Accordingly, a problem resides in that the cost of connection between the pieces of equipment goes up, or much time is consumed in programming the programmable logic controller.
Further, information exchanged between the input/output portions is only information for ON/OFF of input/output. Accordingly, a problem resides in that, when a large amount of data information is exchanged between the pieces of equipment of the production line or when information about the factors of errors caused by, for example, the breakdown of the equipment is exchanged between the pieces of equipment, a dedicated apparatus and a dedicated cable are required, and the installation cost rises.
It is an object of the present invention to provide a robot, a robot system, and a robot control method, which is capable of synchronizing with other robots, capable of performing a logical operation for input/output information, and capable of exchanging data information without raising costs.
As a method for solving the aforementioned problems, the function of connecting a robot to a network is realized. The term xe2x80x9cnetworkxe2x80x9d mentioned here is to, as a method for connection between apparatuses of a production line, carry out data communications according to a predetermined communications method by use of information transmission cables for serial communications not by the use of parallel cables made up of a plurality of lines as mentioned above.
A robot according to a first aspect of the present invention comprises a storage portion in which an operating program for the robot is stored, a main arithmetic portion for analyzing the operating program stored in the storage portion, a sequencer portion from which a signal from the main arithmetic portion is output, a driving portion for driving the robot to which the signal from the main arithmetic portion is input, and a communications portion for communicating with apparatuses connected to a network, and is characterized in that a signal input from an apparatus connected to the sequencer portion to the sequencer portion and a signal input to the communications portion are input to the main arithmetic portion, and a calculation is performed by the main arithmetic portion, and, based on the calculation, a signal is output from the main arithmetic portion to the sequencer portion or to the driving portion.
According to the thus constructed robot, since the robot can be connected to the network, a signal (input information) transmitted from the network and a signal (input information) input from the sequencer portion are calculated, and, by determining the operations of the robot and the external apparatuses while reflecting its calculation result, the operations of the robot and the external apparatuses can be determined in accordance with the usage in the production line. Accordingly, the robot can work as an excellent industrial robot capable of synchronizing with other robots and the belt conveyer of the production line.
Further, since the robot can be connected to the network, communications can be carried out merely by joining only one information transmission cable to the robot even when a plurality of pieces of input/output information necessary to synchronize the robot with other apparatuses are exchanged with the apparatuses. Therefore, costs do not rise. Further, it becomes possible to transmit and receive not only ON/OFF information for input/output but also a large amount of data for an operating program of the robot and the error factor obtained when an error occurs through the network.
Further, in the thus constructed robot, the main arithmetic portion performs a calculation including xe2x80x9cANDxe2x80x9d and xe2x80x9cORxe2x80x9d on the basis of a signal input from the apparatus connected to the sequencer portion to the sequencer portion and a signal input to the communications portion.
According to this structure, it is possible to construct a safer system or a production line in correspondence with actual usage in a factory.
A robot according to a second aspect of the present invention comprises a storage portion in which an operating program for the robot is stored, a main arithmetic portion for analyzing the operating program stored in the storage portion, a sequencer portion from which a signal from the main arithmetic portion is output, a driving portion for driving the robot to which the signal from the main arithmetic portion is input, and a communications portion for communicating with apparatuses connected to a network, and is characterized in that a message signal input from an apparatus connected to the sequencer portion to the sequencer portion and a message signal input to the communications portion are input to the main arithmetic portion, and a calculation is performed by the main arithmetic portion, so that a signal output from the main arithmetic portion to the sequencer portion or a signal output to the driving portion is controlled on the basis of the calculation.
According to the thus constructed robot, it is possible to set the most efficient operating speed or the highest-quality welding condition, and cause the robot to make various movements in correspondence with purposes, in addition to the same effect as that of the first aspect of the present invention.
A robot according to a third aspect of the present invention comprises a storage portion in which an operating program for the robot is stored, a main arithmetic portion for analyzing the operating program stored in the storage portion, a sequencer portion to which a signal from the main arithmetic portion is input, a driving portion for driving the robot to which the signal from the main arithmetic portion is input, a communications portion for communicating with apparatuses connected to a network, and a communications method storage portion in which information about the communications method of the network is stored, and is characterized in that communications are performed on the basis of the information stored in the communications method storage portion even in a network different in the communications method.
According to the thus constructed robot, the robot can be connected to any type of communications-method-network without exchanging the communications portion, in addition to the same effect as that of the first aspect of the present invention.
This robot is further provided with a plurality of input/output terminals, and is further provided with a memory table that stores the allotment of input/output terminals used for the input/output part of: the sequencer portion and input/output terminals used for the input/output part of the communications portion.
According to this structure, a user can inexpensively prepare the input/output terminal for a network and connect the robot to the network without newly adding input/output terminals for the network to a robot controller.
A robot according to a fourth aspect of the present invention comprises a storage portion in which an operating program for the robot is stored, a main arithmetic portion for analyzing the operating program stored in the storage portion, a sequencer portion to which a signal from the main arithmetic portion is input, a driving portion for driving the robot to which the signal from the main arithmetic portion is input, a communications portion for communicating with apparatuses connected to a network, and a history storage portion in which the history of the state of the robot is stored, and is characterized in that information about the history storage portion is output from the communications portion to the network when the stop factor of the robot occurs.
According to this structure, since the robot can be connected to the network, the robot can act as an excellent industrial robot capable of causing a management apparatus connected to the network to restore the production line into a correct working condition while~using the history information by outputting the history of the state of the robot to the network even when the robot installed in the production line is stopped by some factor.
This robot is further provided with a plurality of input/output terminals, and is further provided with a memory table that stores the allotment of input/output terminals used for the input/output part of :the sequencer portion and input/output terminals used for the input/output part of the communications portion.
Further, a computer is used as the apparatus connected to the network, and communications are performed between at least two computers for information output from the history storage portion.
According to this structure, since the robot can be connected to the network, the robot can act as an excellent industrial robot capable of transmitting history information about the movement of the robot to a second computer installed at a remote location and obtaining information necessary for maintenance of the robot even in a remote location.
Further, a computer is used as the apparatus connected to the network, and communications are performed between at least two computers for all of or part of the operating program of the robot, thus storing the operating program of the robot in the storage portion through the communications portion from one of the computers.
According to this structure, since the robot can be connected to the network, the robot-operating program rewritten by the manufacturer of the robot can be stored in the storage portion of the robot that has had a breakdown, and the robot can move according to an appropriate operating program. Accordingly, it is possible to realize an excellent industrial robot whose maintenance can be carried out by the manufacturer of the robot from a remote location.
Further, each of the two computers is provided with an encrypting means for encrypting information to be communicated and a decrypting means for restoring encrypted information into its original condition.
According to this structure, the history information or the operating program of the robot is encrypted, and thereby information can be prevented from leaking out to a third person.
Further, the present invention uses a plurality of robots, an operating means connected to at least one of the robots, a communications portion from which a signal for driving the robot connected to the operating means is output, and a computer used as the apparatus connected to the network, and is characterized in that a signal is input from the computer to a second robot different from the robot that has output the robot driving signal through the. communications portion, and the second robot is driven according to information operated by the operating means.
According to this structure, a user can easily understand the method of operating the robot, and can safely teach the operating method.
Further, in the present invention, there is provided a discrimination means from which a discrimination sign is output to each of the apparatuses connected to the network.
According to this structure, it becomes possible to discriminate information transmitted and received to and from the network, and determine its priority.
A robot control method according to a fifth aspect of the invention comprises a step for storing an operating program of a robot, a step for analyzing a stored operating program, a step for outputting a robot-driving signal in accordance with an analyzed operating program, a step for outputting a signal from an apparatus connected to a network, a step for inputting a signal from an apparatus connected to a sequencer portion, a step for calculating an input signal, and a step for controlling an output of the driving signal on the basis of the calculation.
According to this structures, the movement of an external apparatus can be determined in accordance with the purpose in a production line.
Further, a calculation that includes xe2x80x9cANDxe2x80x9d and xe2x80x9cORxe2x80x9d is performed when the input signal is calculated.
According to this structure, a safer system can be constructed, and a production line corresponding to actual use in the factory can be constructed.
A robot control method according to a sixth aspect of the invention comprises a step for storing an operating program of a robot, a step for analyzing a stored operating program, a step for outputting a robot-driving signal in accordance with an analyzed operating program, a step for inputting a message signal from an apparatus connected to a network, a step for inputting a message signal from an apparatus connected to a sequencer portion, a step for calculating an input message signal, and a step for controlling an output of a signal to be output to the sequencer portion or an output of the robot-driving signal on the basis of the calculation.
According to the thus constructed robot control method, the movement of an external apparatus can be determined in accordance with the purpose in the production line.
A robot control method according to a seventh aspect of the present invention comprises a step for storing an operating program of a robot, a step for analyzing a stored operating program, a step for outputting a robot-driving signal in accordance with an analyzed operating program, a step for storing a history of the state of the robot, and a step for outputting the stored history information to the network when a stop factor of the robot occurs.
According to this structure, since the history of the state of the robot is output to the network, a management apparatus connected to the network can use the history information and restore the production line into a correct working condition even when the robot installed in the production line stops by some factor.